A Gene Drive System for Genetic Control of Malaria Transmission

We are developing gene drive systems in mosquitoes as part of a genetic strategy to control malaria transmission. These strategies will allow the introgression of an autonomous or self-mobilizing effector gene into wild mosquito populations at rates faster than Mendelian inheritance. We have designed a construct for integration into the mosquito genome consisting of key components of the piggyBac transposon and a tissue- and stage-specific promoter. This construct with a linked anti-parasite effector gene present at high frequencies in wild mosquito populations is expected to disrupt malaria transmission and lower human morbidity and mortality.  A transgenic line of Anopheles stephensi was engineered to express the piggyBac transposase in the mosquito germ line using the nanos gene promoter.  This line was crossed with two strains of mosquitoes carrying non-autonomous insertions to monitor their movement by looking at the expression of different phenotypes using the markers Discosoma sp. Red (dsRED) and Enhanced Cyan Fluorescent Protein (eCFP). There are five possible outcomes and three possible phenotypes associated with mobilization in the outcrosses.  Gene amplification will be used to verify the novel chromosome location of any putative remobilized construct. These studies are expected to demonstrate if the transposon is capable of moving the transgene to a different place in the genome, thus validating the basis for an autonomous gene drive system.